<template>
  <div>
    <p>请选择你要购买的书籍</p>
    <ul>
      <li v-for="(val, index) in arr" :key="index">
        {{ val.name }}
        <button @click="goumai(index)">买书</button>
      </li>
    </ul>
    <table border="1" width="500" cellspacing="0">
      <tr>
        <th>序号</th>
        <th>书名</th>
        <th>单价</th>
        <th>数量</th>
        <th>合计</th>
      </tr>
      <tr v-for="(val, index) in arr" :key="index">
        <th>{{ index + 1 }}</th>
        <th>{{ val.name }}</th>
        <th>{{ val.price }}</th>
        <th>{{ val.count }}</th>
        <th>{{ heji[index] }}</th>
      </tr>
    </table>
    <p>总价格为:{{ zongjia }}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [
        {
          name: "水浒传",
          price: 107,
          count: 0,
        },
        {
          name: "西游记",
          price: 192,
          count: 0,
        },
        {
          name: "三国演义",
          price: 219,
          count: 0,
        },
        {
          name: "红楼梦",
          price: 178,
          count: 0,
        },
      ],
      heji: [0, 0, 0, 0],
      zongjia: 0,
    };
  },
  methods: {
    goumai(i) {
      this.arr[i].count++;
      this.heji[i] = this.arr[i].count * this.arr[i].price;
      this.heji.forEach((arr) => (this.zongjia += arr));
    },
  },
};
</script>